Testing process in industrial profiling depends on the characterization of three-dimensional (3-D) objects with high sensitivity in spatial and temporal domains. Ordinary 3-D measurement instruments scan the image area in the temporal domain; therefore, these techniques experience low temporal stability especially for industrial and biomedical sensing. We propose a novel scan-free extended image instrument for sensing the area of 3-D microscopic objects using an interferometric technique with fixed optical parameters, such as resolution, and without mechanical movement. The technique could accelerate the control process in industrial fault detection and images of biological samples could be obtained in a shorter time. First, a stable system for doubling the image area is introduced. Second, the principles underlying the two-dimensional sampling scheme are introduced to record the maximum image area using a dual multiplexing technique at subsampling frequency. Moreover, a standard factor is presented as a figure of merit to determine the exact image area enhancement. Finally, the feasibility of this technique was demonstrated by sensing reflective and transparent objects with image area of up to 4.3-times that of a single-hologram recording using the square scheme. Furthermore, scan-free monitoring of the photolithography process was demonstrated in real-time. The standard deviation of thickness is 0.48 nm, which demonstrates the subnanometer temporal sensitivity of this technique.
Bibliographical noteFunding Information:
Manuscript received July 6, 2017; revised September 29, 2017 and November 13, 2017; accepted January 23, 2018. Date of publication February 8, 2018; date of current version June 1, 2018. This work was supported in part by the Ministry of Science and ICT (MSIT), Korea, under the Information Technology Research Center Support Program (IITP-2017-2016-0-00464) supervised by the Institute for Information & Communications Technology Promotion, in part by the National Research Foundation of Korea (NRF) through the Korean Government (MSIT) under Grant NRF-2017R1A2B2003808, and in part by the Korea University Future Research Grant. The work of B. Tayebi was supported by the BK21 Plus Global Leader Development Division in Brain Engineering. (Corresponding author: Jae-Ho Han.) B. Tayebi and J.-H. Han are with the Department of Brain and Cognitive Engineering, Korea University, Seoul 02841, South Korea (e-mail: firstname.lastname@example.org; email@example.com).
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- Image sampling
- phase detection
- shape control
ASJC Scopus subject areas
- Control and Systems Engineering
- Electrical and Electronic Engineering